What is it about?

The effects of impurities on the Gor'kov and Melik-Barkhudarov (GMB) corrections to an Imbalanced Fermi Gas are investigated. The GMB corrections, or the screening of the two-body interactions, usually referred to as induced interactions, are responsible for the suppression of overestimated superfluid transition temperature (T_c) of a balanced Fermi gas in various systems, geometries and dimensionalities. For the case of an imbalanced Fermi gas, the GMB corrections lower the mean-field (MF) first- and second-order transition lines and the tricritical point. We have shown for the first time that the effects of impurities in the medium are to destroy the GMB corrections pushing the first- and second-order transition curves, and the tricritical point, back to the MF ones. We have also found the effects of the GMB corrections, in the pure and impurity regimes, to the Chandrasekhar-Clogston limit of an imbalanced Fermi gas at unitarity.

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Why is it important?

In cold atoms it is possible to introduce impurities by doping the superfluid with a different species or spin-state. In this case, the impurities would possibly play a different role than that played by impurities in solid state, such as mediating interactions between the background atoms. In such a situation, the impurity would either strengthen pairing or weaken it.


Writing this article was a great experience for me, since it has as coauthors two postdocs with whom I enjoyed to collaborate with. I hope this work can motivate other investigations in this fascinating area.

Heron Caldas
Universidade Federal de Sao Joao del-Rei

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This page is a summary of: The Gor'kov and Melik‐Barkhudarov Correction to an Imbalanced Fermi Gas in the Presence of Impurities, Annalen der Physik, April 2022, Wiley,
DOI: 10.1002/andp.202100564.
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